To measure "treatment" effects, social science researchers typically rely on nonexperimental data. In education, school and teacher effects on students are often measured through value-added models (VAMs) that are not fully understood. We propose a framework that relates to the education production function in its most flexible form and…

The value-added method of Haberman is arguably one of the most popular methods to evaluate the quality of subscores. The method is based on the classical test theory and deems a subscore to be of added value if the subscore predicts the corresponding true subscore better than does the total score. Sinharay provided an interpretation of the added…

By aggregating residual gain scores (the differences between each student's current score and a predicted score based on prior performance) for a school or a teacher, value-added models (VAMs) can be used to generate estimates of school or teacher effects. It is known that random errors in the prior scores will introduce bias into predictions of…

We study the relative performance of two policy-relevant value-added models--a one-step fixed effect model and a two-step aggregated residuals model--using a simulated data set well grounded in the value-added literature. A key feature of our data generating process is that student achievement depends on a continuous measure of economic…

A compositional effect is when pupil attainment is associated with the characteristics of their peers, over and above their own individual characteristics. Pupils at academically selective schools, for example, tend to out-perform similar-ability pupils who are educated with mixed-ability peers. Previous methodological studies however have shown…

Being an expert involves explaining how things are supposed to work, and, perhaps more important, why things might not work as supposed. In this study, researchers surveyed scholars with expertise in value-added models (VAMs) to solicit their opinions about the uses and potential of VAMs for teacher-level accountability purposes (for example, in…

Mean or median student growth percentiles (MGPs) are a popular measure of educator performance, but they lack rigorous evaluation. This study investigates the error in MGP due to test score measurement error (ME). Using analytic derivations, we find that errors in the commonly used MGP are correlated with average prior latent achievement: Teachers…

Since 1992, the UK Government has published so-called "school league tables" summarising the average General Certificate of Secondary Education (GCSE) "attainment" and "progress" made by pupils in each state-funded secondary school in England. While the headline measure of school attainment has remained the percentage…

This study examines the effects of including the summer period on value-added assessments (VAA) of teacher and school performance at the early grades. The results indicate that 40-62% of the variance in VAA estimates originates from the summer period, depending on the outcome (i.e., reading or math achievement gains). Furthermore, when summer is…